The best way to do that is add another analysis chain, which includes a reverse filter. Then use a prefix query.

So the reverse filter will index 1812abcdefg as gfedcba2181. When you use a prefix query on that same analysis chain, 812abcdefg will be converted into gfedcba218* and you'll get your match without an expensive suffix wildcard.

You can also use ngrams / shingles with the reverse approach. So then you'll be indexing reversed fragments, which will match the prefix query. Basically the exact same analyzer you have now, except add a reverse filter to it.

Also, most people who implement this strategy also index the forward direction too, so that they get both prefix and suffix search.